Layered protective structures

ABSTRACT

Protective structures that may be used in various protective gear items, such as helmets and the like. In some embodiments, the protective structure may comprise a layered structure having three distinct layers. The various layers may be selected, arranged, and configured to provide for improved protection at multiple velocities, such as high velocity impacts and low velocity impacts. Some embodiments may also, or alternatively, be configured to provide improved protection and/or durability for multiple impacts at the same portion of the helmet over time.

RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 61/839,314 filed Jun. 25, 2013 andtitled “LAYERED PROTECTIVE STRUCTURES FOR PROTECTIVE GEAR,” whichapplication is incorporated herein by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the disclosure areprovided herein, including various embodiments of the disclosureillustrated in the figures listed below.

FIG. 1 depicts an embodiment of a helmet according to one embodiment.

FIG. 2 depicts a cross-sectional view of the layered, inner shell ofFIG. 1 taken along line 2-2 in FIG. 1.

FIG. 3 depicts an exploded view of the layered, inner shell of FIG. 2.

FIG. 4 is a graph depicting the results of an impact case studyinvolving a helmet incorporating a layered, inner shell according to oneembodiment of the invention compared with other helmets notincorporating the inventive subject matter disclosed herein.

FIG. 5 is a graph depicting the g-forces associated with a first impacton a helmet incorporating a layered, inner shell according to oneembodiment of the invention compared with other helmets notincorporating the inventive subject matter disclosed herein.

FIG. 6 is a graph depicting the g-forces associated with a second impacton a helmet incorporating a layered, inner shell according to oneembodiment of the invention compared with other helmets notincorporating the inventive subject matter disclosed herein.

FIG. 7 is a graph depicting the g-forces associated with a third impacton a helmet incorporating a layered, inner shell according to oneembodiment of the invention compared with other helmets notincorporating the inventive subject matter disclosed herein.

FIG. 8 depicts an embodiment of a middle layer usable with certainembodiments of layered protective structures, the middle layercomprising a plurality of crimped openings.

FIG. 9 depicts another embodiment of a middle layer usable with certainembodiments of layered protective structures.

In the following description, numerous specific details are provided fora thorough understanding of the various embodiments disclosed herein.The systems and methods disclosed herein can be practiced without one ormore of the specific details, or with other methods, components,materials, etc. In addition, in some cases, well-known structures,materials, or operations may not be shown or described in detail inorder to avoid obscuring aspects of the disclosure. Furthermore, thedescribed features, structures, or characteristics may be combined inany suitable manner in one or more alternative embodiments.

DETAILED DESCRIPTION

Embodiments may be best understood by reference to the drawings, whereinlike parts are designated by like numerals throughout. It will bereadily understood that the elements, materials, and components of thepresent disclosure, as generally described and illustrated in thedrawings herein, could be arranged and designed in a wide variety ofdifferent configurations and embodiments. Thus, the following moredetailed description of the embodiments of the apparatus is not intendedto limit the scope of the disclosure, but is merely representative ofpossible embodiments of the disclosure. In some cases, well-knownstructures, materials, or operations are not shown or described indetail in order to avoid obscuring aspects of the disclosure.Furthermore, the described features, structures, steps, orcharacteristics may be combined in any suitable manner in one or morealternative embodiments and/or implementations.

The present disclosure provides various embodiments of layered shellconfigurations that may be used in various protective gear items, suchas helmets. In some embodiments, the layered shell may be configured toprovide for improved protection at multiple velocities. For example,some embodiments may be configured to provide improved impact protectionduring relatively high velocity impacts and also relatively low velocityimpacts. Some embodiments may be also, or alternatively, be configuredto provide improved protection and/or durability for multiple impacts atthe same portion of the helmet over time. Some embodiments may alsoallow for providing a substantially thinner layer of protectivestructure than traditional helmets or other protective gear, while stillproviding one or more of the improved impact protection featuresmentioned herein.

Some embodiments may comprise helmets, such as helmets for use inmotorcycling, skiing, snowboarding, skateboarding, and the like,comprising an interior structure that provides significant reduction ing-force impacts to the head from high velocity and low velocity impacts.In some embodiments, the helmet may also, or alternatively, providesignificantly more multiple impact protection than currently availableprotective interior structures.

Some embodiments may comprise a protective structure comprising multiplelayers of different materials having different thicknesses and densitiesthat are arranged and configured to interact with one another in amanner so as to cushion the head (in embodiments incorporated intohelmets) and protect the head from impacts by dissipating energy fromboth the outside of the helmet (area of impact) and from the interior ofthe helmet by reducing the deceleration velocity of the head during animpact. Some embodiments, as described in greater detail below, maycomprise three distinct layers each comprising different materialsarranged relative to one another and comprising preselected thicknessesthat improve impact protection.

In some such embodiments, the outermost layer may comprise a relativelythick layer made up of a crushable foam material or another materialhaving similar properties. The middle layer may comprise a relativelythin layer made up of a hard plastic material or another material havingsimilar properties configured to spread energy from an impact across alarger area to dissipate the energy transfer to the head associated withthe impact. The innermost layer may comprise a material havingproperties that allow it to compress and rebound, preferably with littledeterioration in shock absorbing properties, such as an ethylene-vinylacetate (EVA) foam or a non-newtonian foam such as a PORON® foam.Although the thickness of the inner layer may vary depending upon thedesired or intended impact protection characteristics, preferably thethickness of the inner and outer layers are both substantially greaterthan the thickness of the middle layer of the protective structure. Insome embodiments, the thickness of the inner layer may be in betweenthat of the outermost layer and the middle layer of the protectivestructure.

Additional details of certain embodiments and implementations will nowbe discussed in greater detail with reference to the accompanyingdrawings. FIG. 1 depicts an embodiment of a helmet 100 according to oneembodiment of the invention. Helmet 100 comprises an outer shell 110 andan inner protective structure comprising an inner shell 120. Asdescribed in greater detail below, inner shell 120 may comprise alayered protective structure. In addition, inner shell 120 may beconfigured to conform to the shape, venting pattern, and/or retentionsystem of outer shell 110. In such embodiments, inner shell 120 may beconfigured to be retro-fittable with an existing outer shell.Alternatively, inner shell 120 may be modular such that variousdifferent inner shells having differing impact protectioncharacteristics may be inserted into a single outer shell in accordancewith particular intended uses of the helmet or other protective gear. Ofcourse, in other embodiments and implementations, the inner shell may bemanufactured together with the outer shell.

FIG. 2 depicts a cross-sectional view of an embodiment of a layeredprotective structure comprising an inner shell that may be used in ahelmet or another item of protective gear. As shown in this figure, thedepicted inner shell 120 comprises three separate layers, each made upof a different material having different properties, thicknesses, and/ordensities. In certain preferred embodiments, each of the three layers ismade up of a different material, comprises a different thickness, andcomprises a different density.

More particularly, inner shell 120 comprises an outer layer 122, amiddle layer 124, and an inner layer 126. Preferably, the materials andthicknesses of the three layers are selected and arranged to interactwith one another during an impact so as to improve impact protectioncharacteristics. In some embodiments, the materials and thicknesses ofthe three layers may be selected and arranged to interact with oneanother during an impact so as to improve impact protectioncharacteristics associated with both high velocity and low velocityimpacts. Additionally, or alternatively, the materials and thicknessesof the three layers may be selected and arranged to interact with oneanother during an impact so as to improve impact protectioncharacteristics associated with repeated impacts at the same, or atleast generally the same, location on the helmet over time.

In some preferred embodiments, the density of the material(s) making upmiddle layer 124 is greater than the density of the material(s) makingup either of the other two layers. Middle layer may comprise arelatively rigid, hard material, such as a hard plastic material. Insome such embodiments, the density of outer layer 122 is greater thanthe density of inner layer 126. It has been discovered that suchconfigurations result in an improved energy transfer and absorptionbetween the three layers that results in improved impact protection.

In some embodiments, outer layer 122 may comprise a material havingenergy absorption characteristics, such as a foam material. Preferably,outer layer 122 comprises a compressible material. In some suchembodiments, outer layer 122 may comprise a crushable foam material.Examples of suitable materials for outer layer 122 that have desiredenergy absorption characteristics include EPS (expanded polystyrene) andEPP (expanded polypropylene). In some preferred embodiments, the densityof the material making up outer layer 122 may be between about 20 g/land about 85 g/l. In some such embodiments, the density of the materialmaking up outer layer 122 may be between about 40 g/l and about 85 g/l.In some such embodiments, the density of the material making up outerlayer 122 may be between about 30 g/l and about 80 g/l. In some suchembodiments, the density of the material making up outer layer 122 maybe between about 20 g/l and about 40 g/l. In some such embodiments, thedensity of the material making up outer layer 122 may be between about60 g/l and about 85 g/l.

In some preferred embodiments, the thickness of outer layer 122 may bebetween about 5 mm and about 30 mm. In some such embodiments, thethickness of outer layer 122 may be between about 10 mm and about 30 mm.In some such embodiments, the thickness of outer layer 122 may bebetween about 10 mm and about 20 mm. It appears that these ranges andmaterials provide for improved protection from low velocity impacts,high velocity impacts, and multiple impacts.

In some embodiments, middle layer 124 may comprise a relatively rigid,non-compressible, and thinner layer of material. For example, middlelayer 124 may comprise an acrylonitrile butadiene styrene (ABS) plasticor another material with similar properties, such as a fiberglass,carbon fiber material, and the like. In some preferred embodiments,middle layer 124 may comprise a thickness of between about 1 mm andabout 2 mm. As described in greater detail below, preferably middlelayer 124 is configured and arranged to isolate and/or spread forces andaccompanying energy associated with exterior impacts from/across innerlayer 126. Middle layer 124 may also be configured to serve as a barrierto protect against penetration by sharp objects, such as rocks, woodsplinters, and the like. Middle layer 124 may comprise an at leastsubstantially smooth surface, and may further, or alternatively,comprise a support in the form of a supported edge crimp, which may beuseful for ventilation. Such a crimp or crimps may also be useful inincreasing the rigidity of middle layer 124 and/or improving thefunctionality of the protective structure by improving the ability ofthe middle layer 124 to spread or otherwise distribute forces betweenthe outer layer 122 and the inner layer 126, as discussed below inconnection with FIG. 8.

In some embodiments, inner layer 126 comprises a compressible, resilientmaterial, preferably configured to avoid crushing deformation that wouldbe associated with certain preferred embodiments of outer layer 122during high velocity impacts. Suitable materials include, for example,ethylene-vinyl acetate (EVA) foam or a non-newtonian foam such as aPORON® foam. In some preferred embodiments, inner layer 126 comprises asofter material than the material making up either of the other twolayers, so as to provide cushion to a head or other body portion duringan impact. In some preferred embodiments, inner layer 126 may comprise athickness of between about 3 mm and about 20 mm. In some suchembodiments, inner layer 126 may comprise a thickness of between about 5mm and about 15 mm. In some such embodiments, inner layer 126 maycomprise a thickness of between about 5 mm and about 10 mm. Inembodiments comprising an inner layer of EVA, such material making upthe inner layer 126 may have a SHORE-A hardness value of between about20 and about 70.

FIG. 3 depicts an exploded view of the layered, inner shell of FIG. 2.As can be better seen in this figure, middle layer 124 is substantiallythinner than either of the other two layers. In addition, as mentionedabove, in some embodiments, outer layer 122 may be thicker than innerlayer 126. As also mentioned above, in certain preferred embodiments,outer layer 122 comprises a crushable material, inner layer 126comprises a material than is resiliently deformable such that crushingor permanent deformation is less likely to occur in inner layer 126 thanin outer layer 122, and middle layer 124 comprises a rigid,non-deformable material configured to absorb and isolate certain impactsfrom outer layer 122 to inner layer 126 and/or spread such impactsacross a greater area from outer layer 122 to inner layer 126 todissipate the forces associated with the impacts.

This combination of layers of different materials having preselectedproperties better protects against both high and low velocity impacts toa helmet or other protective gear item. In some embodiments, thiscombination of layers of different materials having preselectedproperties also provides improved protection against multiplelow-velocity impacts. Without being limited by theory, it is thoughtthat these improvements, and others, may be obtained as follows.

During relatively high velocity impacts, outer layer 122, which providesimpact absorption from the impact arriving from the outside of thehelmet, deforms and/or crushes the crushable foam or other similarmaterial making up outer layer 122, thereby absorbing and releasingenergy from the impact. For purposes of this disclosure, “high velocity”impacts should be considered to encompass those defined by the ASTMvertical drop specifications for helmets and “low velocity” impactsshould be considered those at or less than one-half of those defined bythe ASTM vertical drop specifications for helmets, which may varydepending on the intended use of the helmet. The middle layer 124 thenisolates, or at least reduces, the impact and energy transferred to theinner layer 126. Middle layer 124 may also be configured to spread theimpact energy across a larger area of inner layer 126, thereby resultingin significantly lower energy transfer to the head and increased time ofhead deceleration.

Again, without being limited by theory, during relatively low velocityimpacts, inner layer 126 may compress as the head pushes into the foamor other material making up inner layer 126, thereby decelerating thehead. The outer layer 122 may provide limited, but important, energyabsorption, and may spread the low velocity impact across a larger area,thereby reducing its transfer towards the head. The middle layer 124 mayboth isolate the exterior impact from the inner layer 126 and isolatethe interior layer impact from the outer layer 122.

It is thought that the inventive structures disclosed herein alsoprovide improved protection from multiple, low velocity impacts andimproved durability resulting from such impacts. More particularly,without being limited by theory, it appears that, since the inner layer126 primarily functions to decelerate the head during such impacts (forembodiments in which the layered protective structure comprises ahelmet), the use of compressible, resilient foam materials, or othermaterials with similar properties, allows inner layer 126 to maintainits absorption properties through repeated compressions and expansionswhile conforming back to its original shape, thereby enhancingdurability as well as impact protection.

Through testing, it has been determined that the embodiments andinventive concepts described herein significantly improve g-forcemanagement (reduced g forces) from high velocity impacts consistentwith, for example, motorsports, as well as low velocity impacts,relative to existing helmet technology. Additionally, the embodimentsand inventive concepts described herein may provide improved g-forcemanagement and/or durability from repeated impacts. These experimentalresults are summarized in the examples listed below.

Example 1

Tests were performed on several currently available helmets within themotorcycle, bike, snow sport, and skateboard industries at specificspeeds, drop heights and anvils. FIG. 4 is a graph depicting the resultsof these experiments and comparing peak g-forces for helmets at threedifferent drop heights. The graph compares the results of these testsfor a helmet incorporating a layered, inner shell according to oneembodiment of the invention disclosed herein compared with a best resultfrom among a selection of currently-available helmets from leadingmanufacturers, a worst result from among such helmets, and an averageresult from among such helmets.

The results indicate that the design described herein results insignificantly superior g force reduction compared to currently availablehelmets. More particularly, as shown in FIG. 4, at a first drop fromabout 50 cm (about 3.09 m/s impact speed), an embodiment of theinvention recorded a peak g-force of less than 50 (as shown at 402). Abest result from among the other helmets is shown at 404, a worst resultfrom among the other helmets is shown at 406, and the average resultfrom among the other helmets is shown at 408. As can be seen fromcomparing these results, an embodiment of a helmet according to theinvention achieved a result in terms of g forces at 50 cm that is abouthalf of most other industry helmets.

Example 2

The results from a second test at a drop height of about 78 cm (about3.89 m/s impact speed) are even more dramatic in illustrating theimprovements available from incorporating the inventive conceptsdescribed herein into helmets and/or other protective gear. As shown inFIG. 4, an embodiment of the invention recorded a peak g force just over50 (as shown at 412). A best result from among the other helmets at 78cm is shown at 414, a worst result from among the other helmets is shownat 416, and the average result is shown at 418. As can be seen fromcomparing these results, an embodiment of a helmet according to theinvention achieved a result in terms of g forces at 78 cm substantiallybetter than the other helmets tested.

Example 3

The results from a third test at a drop height of about 160 cm (about5.59 m/s impact speed) illustrate that the benefits from incorporatingthe inventive concepts described herein into helmets and/or otherprotective gear continue for high velocity impacts. As again shown inFIG. 4, an embodiment of the invention recorded a peak g-force of about100 (as shown at 422). A best result from among the other helmets at 160cm is shown at 424, a worst result from among the other helmets is shownat 426, and the average result is shown at 428. As can be seen fromcomparing these results, an embodiment of a helmet according to theinvention achieved a result in terms of g forces at a drop height ofabout 160 cm that is less than half of the average result from among theother helmets, just over one-half of the best helmet, and abouttwo-fifths of the worst helmet.

As illustrated by each of the above-referenced examples, helmetsincorporating protective structures according to the invention mayachieve substantially-improved performance over related helmets for allthree impact velocities. In fact, as also illustrated by each of theseexperimental working examples, helmets incorporating protectivestructures according to the invention experienced g-forces for each ofthe three drop heights that were less than or equal to about 100 g's,which is currently considered to be the desired threshold for concussionavoidance.

Despite this improved performance, some embodiments may be configured toprovide such protection with a smaller thickness than most otherprotective structures. Indeed, in some embodiments, the combinedthickness of the three layers of the protective structure may be lessthan about 30 mm. In some such embodiments, the combined thickness ofthe three layers may be less than or equal to about 24 mm. Indeed, thehelmet used in the above-referenced test results had a thickness of onlyabout 24 mm, including the exterior shell of the helmet, at its thickestpoint. The helmet used in this testing comprised an outer layer of EPSfoam having a thickness of about 10 mm, a middle layer of ABS plastichaving a thickness of about 1 mm, and an inner layer of EVA foam havinga thickness of about 11 mm.

FIG. 5 is a graph depicting the g-forces associated with a first impactat a height of about 20 inches on a helmet incorporating a layered innershell according to one embodiment of the invention compared with otherhelmets at the same height not incorporating the inventive subjectmatter disclosed herein. The data depicted in FIG. 5 corresponds withand represent the same experiment used to obtain the results depicted inthe leftmost portion of the bar graph of FIG. 4.

The g forces associated with the helmet incorporating a layered innershell according to one embodiment of the invention is shown at line 502.Similarly, the g forces associated with two other helmets (neither ofwhich obtained the worst result shown in FIG. 4) are shown at lines 504and 506, respectively.

As shown in FIG. 5, the helmet incorporating a layered, inner shellaccording to one embodiment of the invention exhibited a g-force curvethat indicates the ability to much more effectively spread the forcesdue to helmet impact over time, and to lower the peak forces experiencedby a user/wearer of the helmet. More particularly, the g-force curve at502 is much more flat than either of the other two curves and peaks at anumber about half of either of the other two curves.

FIG. 6 is a graph depicting the g-forces associated with a second impactat the same site as the first impact referenced in FIG. 5 at a height ofabout 31 inches on the helmet incorporating a layered inner shellaccording to the embodiment of the invention used in the experimentrepresented in the curve of FIG. 5 compared with two other helmets alsoused to obtain the results illustrated in FIG. 5.

The g forces associated with the helmet incorporating a layered innershell according to the embodiment of the invention used in theexperiment depicted in FIG. 5 is shown at line 602. Similarly, the gforces associated with the two other helmets used in the same experimentare shown at lines 604 and 606, respectively.

As shown in FIG. 6, the helmet incorporating a layered inner shellaccording to one embodiment of the invention exhibited a g-force curvethat further demonstrates the ability of this protective structure tomuch more effectively spread the forces due to helmet impact over time,and to lower the peak forces experienced by a user/wearer of the helmet.More particularly, the g-force curve at 602 is much more flat thaneither of the other two curves and peaks at a number less than half ofeither of the other two curves.

FIG. 7 is a graph depicting the g-forces associated with a third impactat the same site as the first and second impacts referenced in FIGS. 5and 6 at a height of about 63 inches on the helmet incorporating alayered inner shell according to the embodiment of the invention used inthe experiments represented in the curves of FIGS. 5 and 6 compared withtwo other helmets also used to obtain the results illustrated in FIGS. 5and 6.

The g forces associated with the helmet incorporating a layered innershell according to the embodiment of the invention used in theexperiment depicted in FIG. 7 is shown at line 702. Similarly, the gforces associated with the other two helmets used in the same experimentare shown at lines 704 and 706, respectively.

As shown in FIG. 7, the helmet incorporating a layered inner shellaccording to one embodiment of the invention exhibited a g-force curvethat further demonstrates the ability of this protective structure tomuch more effectively spread the forces due to helmet impact over time,and to lower the peak forces experienced by a user/wearer of the helmet.More particularly, the g-force curve at 702 is much more flat thaneither of the other two curves and peaks at a number well below eitherof the other two curves.

It should be noted that, upon reviewing and comparing FIGS. 4-7, theembodiment of the invention used in the experiments substantiallyoutperformed the competition. This helmet was also able to substantiallyreduce peak g-forces during all test criteria, including high velocityimpacts obtained at drop speeds of about 5.6 m/s, which is the samevelocity as the European Committee for Standardization EN1077 standard,to less than or equal to about 100 g's. This is important since thisamount of force has been considered an approximate threshold foravoiding concussions. Thus, some embodiments of the invention may beable to avoid even a concussion with respect to impacts that for manyother helmets would likely result in serious injury. Moreover, thishelmet was able to achieve such performance while also providing arelatively small thickness profile (about 24 mm).

FIG. 8 depicts an embodiment of a middle layer 800 comprising aplurality of openings 802 configured to be used in a layered protectivestructure. Each of the openings 802 is defined by a plurality of crimpedwalls 804, which extend from a surface 806 of middle layer 800. In thedepicted embodiment, each of the various crimps/walls 804 extends fromsurface 806 at an angle of about 45 degrees. However, it is contemplatedthat in alternative embodiments, the walls defining openings 802 mayextend from a curved or flat surface defining a middle layer of alayered protective structure at angles ranging from about 35 degrees toabout 90 degrees. It is also contemplated that in certain otherpreferred embodiments, the walls defining openings 802 may extend from acurved or flat surface defining a middle layer of a layered protectivestructure at an angle of about 90 degrees.

The openings 802 may correspond with vent openings in the outer shellof, for example, a helmet. However, in addition to serving this ventingpurpose, providing a crimp on a middle layer of a layered protectivestructure may serve to improve the function of the protective structure.As such, it is contemplated that, in some embodiments, such a middlelayer may comprise one or more crimped walls even if such walls do notnecessarily define an opening in the middle layer. In other words, insome embodiments, one or more crimps or similar structures may beprovided to increase rigidity or otherwise improve the function of alayered protective structure, such as by improving the ability of themiddle layer to spread forces between one or more inner and/or outerlayers, irrespective of whether such structures also define openings,such as vent openings.

FIG. 9 depicts another embodiment of a middle layer 900 usable withcertain embodiments of layered protective structures. Middle layer 900comprises a plurality of openings 902 defined by crimped walls 904. Eachof the openings 902 is defined by a plurality of crimped walls 904 thatextend from a surface 906 of middle layer 900. In the depictedembodiment, each of the various crimps/walls 904 extends from surface906 at an angle of about 45 degrees. However, it is contemplated that inalternative embodiments, the walls defining openings 902 may extend froma curved or flat surface defining a middle layer of a layered protectivestructure at angles ranging from about 35 degrees to about 90 degrees.

As depicted in FIG. 9, openings 902 are also arranged in a honeycombfashion adjacent to one another. In other words, each of openings 902forms a hexagonal shape and each opening 902 (other than thosepositioned at a periphery of the honeycomb structure) is positionedadjacent to six other such openings 902 to form a honeycomb structure.However, other embodiments are contemplated in which openings 902 areformed from other polygonal or non-polygonal shapes.

Openings 902 may, in some embodiments, may be aligned with vent openingsin the outer shell of, for example, a helmet. As mentioned above, theraised/crimped structures surrounding openings 902 may be provided toincrease rigidity or otherwise improve the function of a layeredprotective structure, such as by improving the ability of the middlelayer to spread forces between one or more inner and/or outer layers.

Middle layer 900 also comprises a second honeycomb structure comprisingnon-crimped openings 910. Openings 910 may, like openings 902, be formedas hexagons or other polygons and may be arranged such that each side ofthe polygonal opening is positioned adjacent to a corresponding side ofan adjacent polygonal opening 910.

Additional tests were performed using embodiments described herein, theresults of which further establish significant improvement relative toexisting helmet technology. These further experimental results aresummarized in the additional examples listed below.

Example 4

Tests were performed on several currently available helmets at specificdrop heights to assess peak linear acceleration, peak angularacceleration, and Head Injury Criterion (“HIC”), which is acommonly-used measure of the likelihood of head injury resulting from animpact with a helmet. Table 1 below summarizes the results of theseexperiments at a drop height of 51 cm.

TABLE 1 Linear (g) Rotational (krad/s/s) HIC Base 63.9 3.5 105.9 MIPS62.8 2.6 117.2 Embodiment 43.8 3.5 55.0

The table above compares the results of tests at a drop height of 51 cmfor a helmet incorporating a layered, inner shell according to oneembodiment of the invention disclosed herein (“Embodiment”) comparedwith those from a typical, off-the-shelf helmet (“Base”) and those froma particular, high-end brand of helmet (MIPS).

Table 2 below summarizes the results of these experiments at a dropheight of 77 cm.

TABLE 2 Linear (g) Rotational (krad/s/s) HIC Base 83.4 6.5 183.1 MIPS91.5 3.9 242.6 Embodiment 56.2 4.7 96.3

Table 3 below summarizes the results of these experiments at a dropheight of 206 cm.

TABLE 3 Linear (g) Rotational (krad/s/s) HIC Base 151.5 6.6 886 MIPS146.3 5.1 783 Embodiment 114.7 4.6 572

These results indicate that the design described herein results insignificantly better HIC scores, which translate to fewer and lesssevere injuries.

The foregoing specification has been described with reference to variousembodiments. However, one of ordinary skill in the art will appreciatethat various modifications and changes can be made without departingfrom the scope of the present disclosure. Accordingly, this disclosureis to be regarded in an illustrative rather than a restrictive sense,and all such modifications are intended to be included within the scopethereof. Likewise, benefits, other advantages, and solutions to problemshave been described above with regard to various embodiments. However,benefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, a required, or anessential feature or element. The scope of the present invention should,therefore, be determined only by the following claims.

1. A helmet, comprising: a layered protective structure shaped to fitover a head of an individual, the layered protective structurecomprising: a first layer; a second layer positioned internally of thefirst layer, wherein the second layer comprises a more rigid and lesscompressible material than the first layer, and wherein a thickness ofthe second layer is less than a thickness of the first layer; and athird layer positioned internally of the second layer, wherein the thirdlayer comprises a compressible, resilient material configured tocompress and rebound upon being deformed, and wherein a thickness of thethird layer is greater than a thickness of the second layer.
 2. Thehelmet of claim 1, wherein the first layer comprises a crushablematerial.
 3. The helmet of claim 2, wherein the crushable materialcomprises a crushable foam material.
 4. The helmet of claim 3, whereinthe crushable foam material comprises at least one of expandedpolystyrene and expanded polypropylene.
 5. The helmet of claim 1,wherein the second layer comprises a plastic material.
 6. The helmet ofclaim 1, wherein the second layer comprises at least one ofacrylonitrile butadiene styrene plastic, fiberglass, and carbon fibermaterial.
 7. The helmet of claim 1, wherein the third layer comprises atleast one of an ethylene-vinyl acetate foam and a non-newtonian foam. 8.The helmet of claim 1, wherein the second layer comprises a plurality ofopenings each defined by a plurality of crimped walls.
 9. The helmet ofclaim 1, wherein the first layer is positioned adjacent to the secondlayer, and wherein the second layer is positioned adjacent to the thirdlayer.
 10. The helmet of claim 1, wherein the first layer has a densitygreater than a density of the third layer.
 11. The helmet of claim 1,further comprising an outer shell positioned adjacent to the layeredprotective structure such that the layered protective structure ispositioned within the outer shell.
 12. A layered protective structurefor both high and low velocity impacts configured to be used in aprotective gear item, the layered protective structure comprising: anouter layer comprising a first density; an inner layer comprising acompressible, resilient material configured to compress and rebound uponbeing deformed by an impact, wherein the inner layer comprises a seconddensity, and wherein the second density is less than the first density;and a middle layer positioned in between the inner layer and the outerlayer, wherein the middle layer comprises a rigid material configured tospread energy from an impact across a larger area on the inner layer todissipate energy transfer through the inner layer from the impact,wherein the middle layer comprises a third density, and wherein thethird density is greater than the first density and the second density.13. The layered protective structure of claim 12, configured topermanently deform upon receipt of a high velocity impact, wherein theouter layer is configured to avoid permanent deformation upon receipt oflow velocity impacts.
 14. The layered protective structure of claim 12,wherein the middle layer comprises a material configured to inhibitpenetration into the middle layer by impacts with sharp objects.
 15. Thelayered protective structure of claim 12, wherein the outer layer has athickness of between 3 mm and 30 mm.
 16. The layered protectivestructure of claim 15, wherein the outer layer has a thickness ofbetween 10 mm and 20 mm.
 17. The layered protective structure of claim12, wherein the outer layer has a density of between 30 g/l and 80 g/l.18. The layered protective structure of claim 12, wherein the innerlayer has SHORE-A hardness value of between 20 and
 70. 19. The layeredprotective structure of claim 12, wherein the middle layer has athickness of between 1 mm and 2 mm.
 20. The layered protective structureof claim 12, wherein the inner layer has a thickness of between 3 mm and20 mm.
 21. The layered protective structure of claim 20, wherein theinner layer has a thickness of between 5 mm and 10 mm.
 22. The layeredprotective structure of claim 12, further comprising an outer shellpositioned to encase the layered protective structure therein.
 23. Ahelmet, comprising: an outer shell; and an inner shell comprising alayered protective structure positioned within the outer shell, thelayered protective structure comprising: an outer layer comprising acrushable foam material having a density of between about 20 g/l andabout 85 g/l, wherein a thickness of the outer layer is between about 5mm and about 30 mm; an inner layer comprising a compressible, resilientmaterial configured to compress and rebound upon being deformed by animpact, wherein a thickness of the inner layer is between about 5 mm andabout 15 mm, and wherein the inner layer comprises a material having aSHORE-A hardness value of between about 20 and about 70; and a middlelayer comprising at least one of acrylonitrile butadiene styreneplastic, fiberglass, and carbon fiber material, wherein a thickness ofthe inner layer is between about 1 mm and about 2 mm.
 24. The helmet ofclaim 23, wherein the inner layer comprises at least one of anethylene-vinyl acetate foam and a non-newtonian foam.